Chris Hemsworth, Australian hamburger, has a cameo in the new Vacation reboot as Leslie Mann’s nearly-naked, ultra-well-endowed husband. According to the movie’s writer-directors John Francis Daley and Jonathan Goldstein, the process of equipping Hemsworth with his giant movie shlong was vaguely traumatizing.

To choose a specific prosthetic design, they had to expose a stand-in to public humiliation:

“It was definitely one of the more surreal aspects of preparing for this movie,” Goldstein said in an interview with Vulture. “There was a hapless stand-in who first came in when we were looking at the possibilities and he’d put it on and have to show all the different options to us.”

“The morning we shot that sequence, we went into another room in the house we were shooting in, and Chris modeled the eight-inch and the ten-inch options for us,” said Daley. The eight-incher was quickly vetoed: “As big as it would seem, it did not look that big on him. I think it was just because Chris is such a big, hulking dude.”

“He makes the normal-size penis look small,” Goldstein concurred.

Still, other dick issues presented themselves almost immediately. “Chris was playing with it, and handling it,” said Daley, “and we found that there was this metal rod in it that was supposed to make it bendable. The problem was whatever shape you bent it into, it would stay in — which is not like a real dick! So we took the rod out, which allowed it to be more flaccid, but obviously just as huge.”